If this is a one-off for your own use then your ham ticket will cover you a= s long as you fulfill the basic transmission requirements such as transmitt= ing your callsign every 10 minutes. But there are heavy restrictions on unl= icensed use in licensed bands like 433MHz. In that case, field strength max= imums will limit you to about 1 milliwatt into a decent antenna, plus no co= ntinuous or periodic(semi-random is OK) transmission, and there's a maximum= total transmission time within a certain period. Best regards, Bob ________________________________________ From: piclist-bounces@mit.edu on behalf of Neil Sent: Monday, October 7, 2019 2:00 PM To: Microcontroller discussion list - Public. Subject: Re: [EE] Locating object position by radio I was thinking of lower, only because I know I'll get better range and less issues with it. Now that it seems I can use 433Mhz in the US, I'll prob go with that. And if the receivers are the stationary parts, then antenna size is no issue. Cheers, -Neil --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .